Sulfur segregation to oxide/metal interfaces: a comparison of thermally grown and plasma deposited Al{sub 2}O{sub 3}

Conference · Sun Sep 01 04:00:00 EDT 1996

OSTI ID:436361

Hou, P Y; Wang, Z ^[1]; Pruessner, K; Alexander, K B ^[2]; Brown, I G ^[1]

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1. Lawrence Berkeley National Lab., CA (United States)
2. Oak Ridge National Lab., TN (United States)

Segregation of S to oxide/metal interfaces was studied using scanning Auger microscopy after removing the oxide film in ultrahigh vacuum. Two types of alumina films were investigated: one formed from oxidation at 1000 C on Fe-28at.%Al-5at.%Cr; the other was deposited on the same alloy via plasma synthesis, where Al was codeposited with O to form an amorphous Al2O3 film, 0.2 or 0.8 {mu}m thick. Subsequent heat treatment of the deposited film at 1000 C caused it to slowly transform to {alpha}-Al2O3, and the transformation took place at the film/alloy interface. S segregated to the interface during heat treatment. The amount increased with heat treatment time but was much less than that with scales formed by oxidation. Not all the film/alloy interfaces contained S; the behavior was different from the uniform S coverage found under thermally grown scales. S segregation to the film/alloy interface seems to be controlled by availability of interfacial sites rather than bulk diffusion rates.

• Research Organization: Lawrence Berkeley National Lab., CA (United States)
• Sponsoring Organization: USDOE Office of Energy Research, Washington, DC (United States); Electric Power Research Inst., Palo Alto, CA (United States)
• DOE Contract Number: AC03-76SF00098; AC05-84OR21400
• OSTI ID: 436361
• Report Number(s): LBNL--39351; CONF-960928--2; ON: DE97001222; CNN: Contract 8041-05
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CHROMIUM ALLOYS
HEAT TREATMENTS
IMPURITIES
IRON BASE ALLOYS
OXIDATION
SCALING
SEGREGATION
SULFUR